U.S. Pat. Nos. 4,331,430, 4,472,148, 4,826,459, and 4,925,410, all of which are assigned to the assignee of the present invention, describe mechanisms for providing a variety of outboard motor tilt positions. The tilt positions typically include a series of lower trim positions, including one or more shallow water drive positions, and a full up trailering position.
In general, these patents describe tilt mechanisms having a transom bracket that is attached to the transom of a boat, and a swivel bracket that is pivotally mounted to the transom bracket. An outboard motor is rotatably mounted to the swivel bracket. The tilt mechanism allows the operator to change trim positions simply by pushing down on the motor tiller handle and tilting the motor up. A ratchet mechanism allows stepwise movement of a trim pin on the swivel bracket among serially arranged position notches in the transom bracket. This allows the motor to be tilted from the original down position to any higher position, including the full up position. Normally, a tilt strap or the like connects the swivel bracket to the transom bracket to prevent the motor from falling forward of the transom into the boat when the motor is in the full up position. To bring the motor back down to the lower drive position, the motor is tilted up to and slightly beyond the uppermost shallow water drive position, or slightly beyond the full up position, and released. Upon release, the trim pin follows a return path in a closed circuit cam track that returns the trim pin and motor to the down trim position as the motor tilts down.
U.S. Pat. No. 4,925,410 discloses a tilt mechanism lock which is manually operated to selectively lock the motor in the full up position so that the motor does not inadvertently dislodge from bouncing or jarring when the boat is transported. The lock mechanism disclosed in U.S. Pat. No. 4,925,410 operates satisfactorily under most conditions, however, under extremely rough conditions, the bouncing or jarring can cause damage to the lock mechanism or to other structure of the tilt mechanism (e.g. swivel bracket or trim pin). One example of this problem occurs in boating applications where a small outboard motor is used as an auxiliary drive. When a main drive is propelling the boat and the auxiliary drive is stowed in the full up position, pounding from heavy seas or high wave action can cause excessive bouncing and jarring. The excessive bouncing and jarring can damage the structure of the tilt mechanism for the auxiliary drive. Likewise, when an outboard motor is being trailered over the road in the full up position, excessive jarring can damage the structure of the tilt mechanism.
Under most conditions, tilt mechanisms are not damaged and do not break when transported in the full up position. However, some boat owners abuse the tilt mechanism by exposing it to excessive bouncing and jarring when the motor is in the full up position, thereby creating excessive stresses on the tilt mechanism. For these boat owners, it is desirable to provide a way to reduce movement and stresses in the tilt mechanism under excessively rough conditions.